Power Emmet, Sabherwal Sophie, Healy Colm, O' Neill Aisling, Cotter David, Cannon Mary
Department of Psychiatry, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland.
Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland.
Psychol Med. 2021 Jan;51(2):194-200. doi: 10.1017/S0033291720005036. Epub 2021 Jan 27.
Previous systematic reviews and meta-analyses of cross-sectional data assessing the effect of cannabis on cognitive functioning and intelligence show inconsistent results. We hypothesized that frequent and dependent cannabis use in youth would be associated with Intelligence Quotient (IQ) decline. This study is a systematic review and meta-analysis. We searched Embase, PubMed and PsychInfo from inception to 24 January 2020. We included studies with non-treatment seeking samples and pre- and post-exposure measures of IQ. We requested data from authors if summary data was not available from published work. We preregistered our review with PROSPERO (ID no. CRD42019125624). We found seven cohort studies including 808 cases and 5308 controls. We found a significant effect for the association between frequent or dependent cannabis use in youth and IQ change, Cohen's d = -0.132 (95% CI -0.198 to -0.066) p < 0.001. Statistical heterogeneity between studies was also low at I2 = 0.2%. Study quality was moderate to high. This translates to an average decline of approximately 2 IQ points following exposure to cannabis in youth. Future studies should have longer periods of follow up to assess the magnitude of developmental impact.
先前对评估大麻对认知功能和智力影响的横断面数据进行的系统评价和荟萃分析结果并不一致。我们假设青少年频繁使用大麻并产生依赖会与智商下降有关。本研究是一项系统评价和荟萃分析。我们检索了从数据库建立至2020年1月24日的Embase、PubMed和PsychInfo。我们纳入了针对未寻求治疗样本以及智商暴露前和暴露后测量的研究。如果已发表作品中没有汇总数据，我们会向作者索要数据。我们在国际前瞻性系统评价注册库（PROSPERO，注册号CRD42019125624）登记了我们的评价。我们发现了7项队列研究，包括808例病例和5308例对照。我们发现青少年频繁使用大麻或对大麻产生依赖与智商变化之间存在显著关联，科恩d值为-0.132（95%置信区间为-0.198至-0.066），p<0.001。研究之间的统计异质性也较低，I²=0.2%。研究质量为中等至高。这意味着青少年接触大麻后平均智商下降约2分。未来的研究应该进行更长时间的随访，以评估发育影响的程度。
